<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
        .first{
            width: 40px;
            height: 40px;
            background-color: yellow;
            float:left
        }
        .second{
            width: 80px;
            height: 80px;
            background-color: red;
            float:left
        }
        .third{
            width: 60px;
            height: 60px;
            background-color: blue;
            
        }
    </style>
  </head>
  <body>
    <!-- float -->
    <div class="first">x</div>
    <div class="second">y</div>
    <div class="third">z</div>

  </body>
</html>
